import rospy
from std_msgs.msg import String
 
def callback(data):
    rospy.loginfo(rospy.get_caller_id() + "I heard %s", data.data)
    
def listener():

    rospy.init_node('listener', anonymous=True)
 
    rospy.Subscriber("chatter", String, callback)
 
    rospy.spin()
 
if __name__ == '__main__':
    listener()
